The Blood Fountains are places where Kain can gain more strength,
faster magic regeneration, the Beguile Form, resistance to rain, and
resistance to snow. Each Blood Fountain can be used once, and woe to
the vampire who becomes greedy, and tries drinking a second time.

The locations of the Blood
Fountains can be found along Kain's path, generally in caves located
just off the beaten path. Check out The Plot
for descriptions of their locations. Or look here for graphically intensive spoilers on their
locations.

Tip: If you're walking along, and you notice a path breaking away from
the main path, try Zooming out, if you see a cave entrance, it's
possibly a Blood Fountain. (or a dungeon, or a bandit hideout,
or...)

The Spirit Forges

The Spirit Forges let you sacrifice blood for objects.

Yes, there is indeed
one Spirit Forge for each object. The Spirit Forges are often hidden
behind stone doors that only open during full moons. Some of the
Spirit Forges, especially ones that give Kain more powerful objects,
are more concealed, and require a bit of searching to find.

Each of the Spirit Forges
also has a secret back door which lets Kain gain access to it from a
distant location. This is particularly useful when Kain gains the Mind
Control spell. (Nothings says that is must be Kain's blood that is
sacrificed!)

The Bat Flight Beacons

The Bat Flight Beacons are points Kain can fly to in Bat Form. Each beacon has
to be triggered before it can be used.

The obvious use for Bat Beacons is to return to that location after
taking a side trip to another part of the world. As it happens, many
of the Bat Beacons are situated near Moon-Key Doors, which is quite
convenient when the full moon rises.

Look here for descriptions of where all of
them are located in the game.